Cutting device



Jan. 14, 1958 M. P. MATTHEW CUTTING DEVICE Original Filed April 27, 1954 INVENTOR. MORTON P MATTHEW MA-1M2 ATTOR N EY CUTTING DEVICE.

Morton P. Matthew, TakomaPark, Md.

Original application April 27, 1954, Serial No. 425,811, now Patent No. 2,803,303, dated August 20, 1957. Dizided and this application April 5, 1956, Serial No. 57 ,441

4 Claims. (Cl. 30-310) This application is a division of application Serial No. 425,311, filed April 27, 1954, now Patent No. 2,803,303, Aug. 20, 1957.

This invention relates to cutting devices and more particularly to devices for cutting sheet material.

It is an object of thepresent: invention to provide a cutting tool adapted to eificiently and accurately cut circular pieces of cardboard or other soft sheet material, means being provided for varying the diameter of the cut pieces.

Other objects and a better understanding of the invention will become apparent from the following detailed description taken in conjunction with the accompanying drawing, wherein:

Figure l is a top plan View of the cutting tool;

Fig. 2 is a front elevational view thereof;

Fig. 3 is a side elevational view thereof looking from the right of Fig. 2;

Fig. 4 is a transverse sectional view taken along the line 99 of Fig. 3;

Fig. 5 is a fragmentary side elevational view showing the needle-carrying bar in a reversed position for cutting pieces of circular sheet material of relatively large diameter, and

Fig. 6 is a fragmentary exploded view of the cutting tool.

Referring now to the drawing there is shown a rotary cutter indicated generally at 33 and including a block 39 of plastic or other suitable material of substantially trapezoidal shaped cross section (Fig. 4).

The tool 33 is designed for cutting circles of varying diameter in cardboard or other soft sheet material. The forward end of the block 39 is provided with a rectangular groove 48 receiving therewith and providing a shoulder ll for one longitudinal edge of a cutting blade 4-2 having an inclined cutting edge 43. The blade 42 is secured in position by a clamping plate 44 received within the groove 49 and a screw 45 passing through plate 44 and screw threaded into the block 39.

The undersurface of the block 39 (Fig. 4) is provided with a pair of substantially parallel, longitudinal extending grooves 46 and 47 extending substantially the length of the block itself. Either of the grooves 46 and 47 is adapted to receive therewithin for longitudinal sliding movement a flat bar fixedly carrying at one end a needle 49, serving as a pivot, the point of needle 49 being aligned substantially longitudinally with the point of the cutting blade 42. The portion of the block 39 intermediate the grooves 46 and 47 near the end thereof remote from the blade 42 is provided with an elongated slot 50 therethrough in which is positioned an adjustment screw 51 having an enlarged knurled head 52 and a collar 53. A washer 54 is provided intermediate the top of block 39 and collar The undersurface of the block 39 intermediate the grooves 46 and 47 and adjacent the end thereof remote from blade 42 is cut away as at 55 to accommodate a transverse lug 56 screwed onto the lower end of the adjustment screw 51, the lug 56 along one longitudinal edge being integrally formed with an upwardly extending flange 57 extending upwardly alongside the bar 48. Upon tightening the adjustment screw 51, the lug 56 will be brought to bear against the lower edge of the bar 48, whereby to lock the position of the same within either groove 46 or 47 relative to the blade 42. Thus, the distance between the needle 49 and the point of blade 42 may be adjusted so as to vary the diameter of the circular material to be cut.

The bar 48 may also be removed and reversed as shown in Fig. 5, effectively doubling the range of diameters. In this reversed position, the needle 49 will be extendable beyond the block 39.

The slot 50 allows longitudinal movement of the thumb screw 51 and lug 56, permitting the bar $8 to be adjusted so that the needle 49 may-underlie any position along the slot 50. It should be apparent that without slot :56, that is if the screw 51 and lug 56 were fixed with respect to member 39, it would not be possible to set needle 49 at the location of the screw 51 and lug 56.

In operation, the cutting tool 38 is pushed straight downwardly on to the surface of the material to be cut, the needle 4? penetrating the material and anchoring itself in the supporting surface of wood, cardboard or the like. Simultaneously, the blade 42 will also penetrate the material to be cut, the tool 38 is then rotated about the needle 49 as a pivot point, the cutting edge 43 of blade 42 cutting a perfect circle in the material.

As shown in Fig. 4, the block 39 is symmetrical and the bar til may also be mounted for sliding movement within the groove 47, with the lug 56 being then rotated degrees. This alternate position will make it possible to use the cutting tool 33 in a counterclockwise di rection, whereupon the blade must be reversed and clamped in the other shoulder as well as changing the bar 48 to the outer groove 47. Thus, the tool may be used by either right or left handed persons with equal facility.

It will also be apparent that the bar 48 may be replaced by any one of a number of longer bars, extending thereby the radii range of the tool.

The advantages of the rotary cutting tool 38 are as follows: it is light in weight, small in size and can be fabricated at a relatively low cost. It may be easily and readily sharpened by simply replacing the blade 42. Sirnplicity of operation is afforded, the tool requiring the use of only one hand. By adjusting the blade 42, within the groove ll), it is possible to scribe or cut through the material to a prescribed depth. The cutting edge 43 results in a smooth accurate edge of cut. A wide range of possible radii is provided in combination with the ability of the tool to cut very small circles.

Further, the sloping sides of the cutter block force the operator to hold the block down firmly on the material thus giving the best possible cutting action. The relatively narrow width of the blade penetrating the material permits very small diameter circles to be cut cleanly and without damage to the blade. Furthermore, the relatively narrow width of the blade permits very short arcuate cuts to be made.

While various changes may be made in the detail construction, it shall be understood that such changes shall be within the spirit and scope of the present invention as defined by the appended claims.

I claim:

1. A rotary cutting tool comprising an elongated block, a cutting blade mounted at one end of said block, a longitudinal groove on the undersurface of said block, a bar slidable longitudinally within said groove, a pointed pivot fixedly carried by said bar, said block having an elongated slot passing downwardly from the upper surface of said block and extending substantially parallel to said groove, 9. thumb screw passing downwardly through said slot, and a transverse lug screw-threaded onto the lower end of said thumb screw and adapted to bear on the lower edge of said bar whereby to lock the position of said pivot relative to said cutting blade.

2. A rotary cutting tool comprising an elongated block having a cutting blade mounted at one end thereof, at least a portion of the undersurface of said block presenting a substantially flat base, a pair of longitudinal laterally spaced grooves provided on the undersurface of said block, a bar slidable longitudinally within either of said grooves, a pointed pivot fixedly carried by said bar, said block having an elongated slot passing downwardly from the upper surface of said block at the end remote from the blade, said slot extending substantially parallel to said grooves and intermediate thereof, a thumb screw passing downwardly through said slot, and a transverse lug screw-threaded onto the lower end of said thumb screw and adapted to bear on the lower edge of said bar whereby to lock the position of said pivot relative to said cutting blade, the undersurface of said block below said slot being recessed, whereby said lug may be maintained above the plane of said flat base.

3. A rotary cutter comprising an elongated block, a transverse cutting blade adjustably mounted at one end of said block, said block having a pair of laterally spaced grooves extending longitudinally at substantially right angles to said transverse cutting blade and being opened at the end remote from said cutting blade, a removable bar slidable within either of said grooves, a sharpened point fixedly depending from said bar at one end thereof, and releasable means for locking the position of said bar within said grooves, whereby said bar may be positioned in either groove and whereby the relationship of the point carrying end of said bar may be reversed with respect to said blade.

4. A rotary cutting tool comprising an elongated block, a cutting blade adjustably mounted at one end of said block, longitudinally extending groove on the undersuriace of said block, said groove being open at the end of said groove remote from said blade, a bar slidable within said groove, means for locking the position of said bar within said groove, and a pointed pivot fixedly carried at one end of said bar, the longitudinal position of said bar being reversible, whereby said pointed pivot is located either substantially adjacent said cutting blade for cutting small circles or at a point beyond the end of said block remote from said cutting blade, and at any point there between.

References Cited in the file of this patent UNITED STATES PATENTS 160,015 Goodnow Feb. 23, 1875 318,333 Warden May 19, 1885 1,241,018 Rawles a- Sept. 25, 1917 2,046,435 Turnquist July 7, 1936 2,716,282 Kromsten Aug. 30, 1955 

